Imaging Surveillance for Stage IIIB Colon Cancer

Risk Stratification and Surveillance Intensity

80% of recurrences occur within the first 2-2.5 years after surgery, and 95% occur by 5 years, according to the American Society of Clinical Oncology 1, 2
Patients at higher risk of recurrence, such as those with N2a disease, should be considered for testing at the more frequent end of the recommended range, as suggested by the American Society of Clinical Oncology 1, 2
The National Comprehensive Cancer Network recommends that patients with stage IIIB colon cancer, including those with N2a disease, undergo intensive surveillance due to their high-risk status 1

The American Society of Clinical Oncology recommends CT imaging of the chest, abdomen, and pelvis every 6-12 months for the first 3 years after surgery for patients with stage IIIB colon cancer 1, 2
For high-risk patients like those with N2a disease, imaging every 6 months is reasonable for the first 3 years, according to the American Society of Clinical Oncology 1, 2
The European Society for Medical Oncology suggests that annual imaging for 3 years is the minimum standard, but more frequent surveillance (every 6 months) is appropriate for stage III disease 3, 4

The National Comprehensive Cancer Network recommends history and physical examination every 3 months for the first 2 years, then every 6 months for years 3-5, for patients with stage IIIB colon cancer 5, 1, 2, 4
The National Comprehensive Cancer Network also recommends CEA testing at the same intervals: every 3 months for 2 years, then every 6 months for years 3-5, for patients with stage IIIB colon cancer 5, 6, 1, 2, 4
Colonoscopy is recommended at 1 year after resection, or 3-6 months postoperatively if preoperative colonoscopy was not performed due to obstruction, according to the National Comprehensive Cancer Network 5, 1, 2, 8

The American Society of Clinical Oncology recommends that surveillance tests should not be performed if the patient is not a surgical candidate or cannot tolerate systemic therapy due to severe comorbidities 1, 2
PET scans are not recommended for routine surveillance, but may be considered before surgical resection when recurrence is suspected or an isolated resectable lesion is detected, according to the National Comprehensive Cancer Network and the European Society for Medical Oncology 1, 2, 7, 8